#include<cstdio>//uncle-lu
#include<algorithm>
template<class T>void read(T &x)
{
	x=0;int f=0;char ch=getchar();
	while(ch<'0'||ch>'9') { f|=(ch=='-'); ch=getchar(); }
	while(ch<='9'&&ch>='0') { x=(x<<1)+(x<<3)+(ch^48); ch=getchar(); }
	x = f ? -x : x;
	return ;
}

int n;
int F[10010][10010];
int line1[100010], line2[100010];

int main()
{
	read(n);
	for (int i = 1; i <= n; i++) 
		read(line1[i]);
	for (int i = 1; i <= n; i++) 
		read(line2[i]);
	
	for (int i = 1; i <= n; i++) 
	{
		for (int j = 1; j <= n; j++) 
		{
			if(line1[i] == line2[j])
				F[i][j] = std::max(F[i][j], F[i-1][j-1] + 1);
			F[i][j] = std::max(F[i][j], F[i-1][j]);
			F[i][j] = std::max(F[i][j], F[i][j-1]);
		}
	}

	printf("%d", F[n][n]);
	return 0;
}
